Publications by authors named "Katso R"

Following the discovery of cell penetrant pyridine-4-carboxylate inhibitors of the KDM4 (JMJD2) and KDM5 (JARID1) families of histone lysine demethylases (e.g., 1), further optimization led to the identification of non-carboxylate inhibitors derived from pyrido[3,4-d]pyrimidin-4(3H)-one.

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Article Synopsis
  • Optimization of KDM6B HTS hit 12 led to the discovery of two new compounds, 34 and 39, as KDM4 family histone lysine demethylase inhibitors.
  • These compounds show strong activity with IC50 values ≤ 100 nM in biochemical assays and demonstrate high selectivity against KDM6B.
  • Additionally, compounds 34 and 39 are effective at inhibiting KDM5C with IC50 values in the range of 100-125 nM.
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In March 2014, GSK announced a number of new strategic investments in Africa. One of these included investment of up to 25 million Pounds Sterling (£25 million) to create the world's first R&D Open Lab to increase understanding of non-communicable diseases (NCDs) in Africa. The vision is to create a new global R&D effort with GSK working in partnership with major funders, academic centres and governments to share expertise and resources to conduct high-quality research.

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The jumonji (JMJ) family of histone demethylases are Fe2+- and α-ketoglutarate-dependent oxygenases that are essential components of regulatory transcriptional chromatin complexes. These enzymes demethylate lysine residues in histones in a methylation-state and sequence-specific context. Considerable effort has been devoted to gaining a mechanistic understanding of the roles of histone lysine demethylases in eukaryotic transcription, genome integrity and epigenetic inheritance, as well as in development, physiology and disease.

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The biological complexity associated with the regulation of histone demethylases makes it desirable to configure a cellular mechanistic assay format that simultaneously encompasses as many of the relevant cellular processes as possible. In this report, the authors describe the configuration of a JMJD3 high-content cellular mechanistic imaging assay that uses single-cell multiparameter measurements to accurately assess cellular viability and the enzyme-dependent demethylation of the H3K27(Me)3 mark by exogenously expressed JMJD3. This approach couples robust statistical analyses with the spatial resolving power of cellular imaging.

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Receptor-linked class I phosphoinositide 3-kinases (PI3Ks) induce assembly of signal transduction complexes through protein-protein and protein-lipid interactions that mediate cell proliferation, survival, and migration. Although class II PI3Ks have the potential to make the same phosphoinositides as class I PI3Ks, their precise cellular role is currently unclear. In this report, we demonstrate that class II phosphoinositide 3-kinase C2beta (PI3KC2beta) associates with the Eps8/Abi1/Sos1 complex and is recruited to the EGF receptor as part of a multiprotein signaling complex also involving Shc and Grb2.

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The nuclear receptor (NR) superfamily represents a major class of drug targets for the pharmaceutical industry. Strategies for the development of novel, more selective and safer compounds aimed at these receptors are now emerging. Reporter assays have been used routinely for the identification and characterisation of NR ligands.

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The authors describe the use of modified baculoviruses containing mammalian expression cassettes (BacMam technology) in steroid nuclear receptor reporter assays designed for screening and profiling agonist and antagonist compounds. Baculo-viruses were constructed that express full-length human genes for mineralocorticoid receptor (MR), glucocorticoid receptor (GR), progesterone receptor A (PR-A), and progesterone receptor B (PR-B) from the cytomegalovirus immediate early promoter. A virus carrying the mouse mammary tumor virus-firefly luciferase (MMTV-Luc) cassette was generated to provide a suitable reporter construct.

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The phosphoinositide 3-kinase (PI3K) family of enzymes is recruited upon growth factor receptor activation and produces 3' phosphoinositide lipids. The lipid products of PI3K act as second messengers by binding to and activating diverse cellular target proteins. These events constitute the start of a complex signaling cascade, which ultimately results in the mediation of cellular activities such as proliferation, differentiation, chemotaxis, survival, trafficking, and glucose homeostasis.

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The 3-phosphorylated inositol lipids fulfill roles as second messengers by interacting with the lipid binding domains of a variety of cellular proteins. Such interactions can affect the subcellular localization and aggregation of target proteins, and through allosteric effects, their activity. Generation of 3-phosphoinositides has been documented to influence diverse cellular pathways and hence alter a spectrum of fundamental cellular activities.

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Phosphorylation of protein kinase C (PKC) provides an amplitude control that operates in conjunction with allosteric effectors. Under many conditions, PKC isotypes appear to be highly phosphorylated; however, the cellular inputs that maintain these phosphorylations are not characterized. In the present work, it is shown that there is a differential phosphorylation of PKCdelta in adherent versus suspension cultures of transfected HEK-293 cells.

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H-Ryk is an atypical receptor tyrosine kinase that is expressed in a differentiation-specific manner in epithelial tissues. We have previously shown by in situ hybridization and immunohistochemistry that H-Ryk is overexpressed in malignant ovarian tumors. In addition, we have demonstrated that overexpression of H-Ryk is transforming in vitro and in vivo.

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H-Ryk is an atypical receptor tyrosine kinase which differs from other members of this family at a number of conserved residues in the activation and nucleotide binding domains. Using a chimeric receptor approach, we demonstrate that H-Ryk has impaired catalytic activity. Despite the receptor's inability to undergo autophosphorylation or phosphorylate substrates, we demonstrate that ligand stimulation of the chimeric receptor results in activation of the mitogen-activated protein kinase pathway.

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Abnormalities in the function of receptor tyrosine kinases (RTKs) have been demonstrated to be important in the pathogenesis of cancer. H-Ryk, a new member of the RTK family, is an unusual RTK in that it is catalytically inactive because of amino acid substitutions of conserved residues in the catalytic domain. We show by immunohistochemistry that it is expressed in the epithelium, stroma, and blood vessels of normal tissues.

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The recent advances in the understanding of the pathogenesis of ovarian cancer have been helpful in addressing issues in diagnosis, prognosis and management. The study of ovarian tumours by novel techniques such as immunohistochemistry, fluorescent in situ hybridisation, comparative genomic hybridisation, polymerase chain reaction and new tumour markers have aided the evaluation and application of new concepts into clinical practice. The correlation of novel surrogate tumour specific features with response to treatment and outcome in patients has defined prognostic factors which may allow the future design of tailored therapy based on a molecular profile of the tumour.

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The discoidin domain receptor (DDR) is a new class of receptor tyrosine kinase that is distinguished by a unique extracellular domain homologous to the lectin Discoidin I found Dictyostelium discoideum. A cosmid was isolated from a human chromosome 6 cosmid library containing the DDR gene. A complete genomic contig of the DDR gene was constructed from seven subclones of the cosmid.

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Background: Protein tyrosine kinases play an important role in cellular metabolism as key components of signal transduction pathways. They are involved in cellular growth, differentiation, and development. Receptor tyrosine kinases (EGF receptor and c-erbB2) have been shown to be important in the pathogenesis of cancer.

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